100 hp zuki falls on face

[lady athens]

I have read through the posts and can't find my answer.
'91 suzuki 100hp runs great in drive way with earmuffs on. I can rev up and down to idle no problem. When I put it in the river it will hardly idle and will try to go for a few seconds then I had the carbs adjusted, prop changed and a termostat changed last year and it ran fine. It has been sittin for the winter until now.

When I run it in the driveway there is good water flow coming out of the pilot hole but hardly any thing coming out of the water discharge holes in the rear of the engine. Don't know if thats normal. I have new gas and oil going to it.

Also even when it ran good the most rpms I could get out of it was about 3000. The specs say that the operating range at WOT is 5000 to 5600. It has always been low and still is after changing prop. This 100 hp is on a '90 25ft Ercoa that seems to be a heavy vessel.

Thanks in advance for your time!!

 

[lady athens]

Re: 100 hp zuki falls on face

By the way it is a 100 hp v4 two cycle with oil injection with micro link ignition.

 

[deejaycee_2000]

Re: 100 hp zuki falls on face

It is normal for not much water to come out the discharge hole when running on muffs ..... 25ft boat is huge, no wonder you can't push more than 3000rpm ....

 

[lady athens]

Re: 100 hp zuki falls on face

thanks for that I was worried about it. Any idea why it will run in driveway but not river.

 

[waffles1]

Re: 100 hp zuki falls on face

An engine is not under a load while running of the hose so if there's a problem it may go undetected. When you back it in the water it puts a small load on the engine even sitting in idle on the trailer. It takes a little bit more umph to run water through the pump and out the exhaust where a little back flow pressure occurs. There could be several areas that could be the problem here. Dirty carbs, old gas, bad plugs, etc....What maintenance have you done to the motor? As for as your rpms, what size prop are you running?

 

[deejaycee_2000]

Re: 100 hp zuki falls on face

Time for a good carb clean ...

 

[lady athens]

Re: 100 hp zuki falls on face

yep the local mech. said carb clean is in store. The prop is 18 x 19 no hydrofoil or anything

 

[waffles1]

Re: 100 hp zuki falls on face

Talk to your mechanic doing the carbs and ask what pitch prop he reccomends. It sounds like you are over propped and that's why you can't get the rpms up to around 5500 where they should be.

 

[bowhuntrrl]

Re: 100 hp zuki falls on face

yep the local mech. said carb clean is in store. The prop is 18 x 19 no hydrofoil or anything

You are way, way over propped !!! I have a 16' CC and a DT-85 Suzuki , and I have to run a 14x15 pitch to get to 5400 rpm WOT. You might even need to go lower than that.

It also sounds like you need a good carb cleaning/overhaul, link and synch.